News Release No. 404

MISSOURI DEPARTMENT OF NATURAL RESOURCES' PROJECT
TO MAP SEISMIC HAZARDS IN METROPOLITAN ST. LOUIS AREA

Volume 33-404

Contact: Jim Palmer

(For immediate release)

573-368-2100

JEFFERSON CITY, MO, SEPT. 29, 2005 -- The Missouri Department of Natural Resources is acquiring and developing data for the St. Louis Area Earthquake Hazards Mapping Project. In addition to mapping, the department's Division of Geology and Land Survey (DGLS) will merge geotechnical engineering data from various public sources such as the Missouri Department of Transportation, the St. Louis Metropolitan Sewer District and the Army Corps of Engineers. This database will assist in determining site conditions for construction projects meeting the 2003 International Building Code seismic design requirements recently adopted by St. Louis County.

"Geologic hazards mapping can provide extremely valuable data for sound economic decisions," said Mimi Garstang, DGLS director. "We are pleased that this project will serve as a useful tool for both the private and public sector to be better informed about which areas in the greater St. Louis area have higher risk and which areas have lower risk and reduced requirements for seismic design considerations."

This resource tool will serve both construction engineering projects and municipalities throughout Metropolitan St. Louis.

"This can be significantly beneficial to us to have an independent source reference to identify the proper site classification for earthquake design," said Michael E Werner, deputy director of St. Louis County Public Works Department. Werner's department is responsible for the enforcement of building, mechanical, electrical and plumbing codes in unincorporated St. Louis County and the incorporated areas of St. Louis that contract with St. Louis County.

Bill Graham, senior geotechnical engineer with TSi Engineering, recently commented that he had made use of the data set on several projects, primarily to assess general subsurface conditions in a given area. "It is a valuable compilation of detailed data, essentially the logs of a number of borings that have been collected from different sources and made available electronically to users," Graham explained. "For geotechnical engineers in private practice it will provide data upon which to base preliminary assessments of subsurface conditions and from which to make better (more accurate) plans for detailed subsurface investigations."

The database and mapping project should be useful in mitigating potential earthquake damage to structures and lessening the economic impact of a moderate or greater earthquake by defining soil and geologic characteristics of local sites. Soft, saturated soils can liquefy or amplify shaking during an earthquake, causing damage to poorly designed or built structures. Areas that have thin, stiff soils over dense bedrock, such as many locales in eastern Missouri, do not amplify seismic waves and have lower potential for structural damage. New hazard maps will refine our understanding of potential liquefaction or amplification and show those areas that have low potential for earthquake damage.

For more information about the department's geologic mapping at the Division of Geology and Land Survey, please contact the Missouri Department of Natural Resources' DGLS at 800-361-4827 or 573-368-2100, or visit www.dnr.mo.gov/geology.

For department news releases on the Web, visit www.dnr.mo.gov/newsrel. For a complete listing of the department's upcoming meetings, hearings and events, visit the department's online calendar at www.dnr.mo.gov/calendar/search.do.

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